Idiopathic hepatic uptake of (99m)Tc methylene diphosphonate: a case report.

OBJECTIVE Two sequential (99m)Tc methylene diphosphonate (MDP) scans were performed on a 42-y-old woman with insulin-dependent diabetes mellitus, chronic right pyelonephritis and anemia. The initial scan showed reduced skeletal uptake with intense and diffuse hepatic uptake. Because these findings were similar to those seen when excessive hydrolyzed-reduced (99m)Tc colloids are present in the radiopharmaceutical, the scan was repeated after an adequate time delay. Increased skeletal uptake was evident in the second scan, but the hepatic uptake persisted. Although there are numerous causes of soft tissue activity on (99m)Tc MDP bone scans, the responsible pathologic entity is not always clear. This study reviews several possible reasons for such uptake, although the exact mechanism in this case remains conjectural.